During the past decade there has been a rapid growth of research in the areas of nanomaterials and nanoscience because of the realization that these small size materials can be used in a multitude of industrial and biomedical processes. The great potential of using nanoscale particles for different biological and medical applications including gene and drug delivery, biosensing, diagnostic, tissue engineering was widely documented during last several years [Refs. 1-6].
Most investigations were focused on studying the effects of different nanomaterials on the cellular morphology, behavior and functions, and selective killing in order to understand how such structures would affect animals and humans at various levels [Refs. 7-11]. Moreover, thorough studies and reliable information regarding the effects of nanomaterials such as carbon nanotubes on plant physiology and plant development at the organism level are very limited. However, there is an extensive interest to investigate the ability of nanoparticles to penetrate plant cell walls and work as smart treatment-delivery systems in plants. Several research groups reported that different types of nanoparticles are able to penetrate plant cell walls. Thus, it was shown that gold-capped mesoporous silica nanoparticles (MSNs) were able penetrate cell wall and delivery DNA into plant cell by using a bombardment method [Ref. 12]. Lately, Liu and coauthors [Ref. 13] demonstrated the capability of single-walled carbon nanotubes (SWNTs) to penetrate the cell wall and cell membrane of tobacco cells. Additionally, methods of visualization of carbon-coated iron nanotubes in plant cells using pumpkin plants as model were reported [Ref. 14]. There is an extensive interest in applying nanoparticles to plants for agricultural and horticultural use [Ref. 15]. To achieve the goals of “nano-agriculture”, detailed studies on the effects of nanotubes on seed germination and development of seedlings of valuable agricultural plant species are needed. Penetration of plant seeds could be more complicated as compared to plant cell walls and mammalian cell membranes due to the significant thickness of seed coat covering the whole seed [Ref. 16]. However, it was shown that seed coats of different plant species are selectively permeable to heavy metal ions such as Pb2+ and Ba2+ [Ref. 17]. Based on this observation it is logical to assume that some nano-size materials will be able to penetrate plant seed coats and affect seed germination. It would therefore be desirable to develop a method of increasing the probability and rate of seed germination using carbon nanomaterials. It would also be desirable to develop a method of increasing water uptake in seed using carbon nanomaterials. In addition, it would be desirable to develop a method for increasing vegetative biomass using carbon nanomaterials.